Electric shifting arrangement for change speed transmissions



Oct. 18, 1960 WOLF-DIETER BENSINGER ETAL 2,956,444

ELECTRIC SHIFTING ARRANGEMENT FOR CHANGE SPEED TRANSMISSIONS 2 Sheets-Sheet 1 Filed Ray 27. 1959 CLUTCH INVENTORS WOLF D|ETER BENSINGER BY KARL DIETRIGH KURZ TRANSMISSION Oct. 18, 1960 WOLF-DIETER BENSINGER ETAL 2,956,444

ELECTRIC SHIFTING ARRANGEMENT FOR CHANGE SPEED TRANSMISSIONS Filed May 27, 1959 2 Sheets-Sheet 2 Fuel Adjusting Device INVENTORS WOLF-DIETER BENSINGER KARL DIETRICH KURZ United States Patent Ofiice 2,956,444 Patented Oct. 18, 1960 ELECTRIC SHIE'IIN G ARRANGENIENT. FOR

CHANGE SPEED TRANSMISSIONS Wolf-Dieter Bensinger, Stuttgart-Unterturkheim, and Karl Dietrich Kurz, Stuttgart-Rohracker, Germany; assignors to Daimler-Benz Aktiengesellschaft, Stuttgart-Unterturkheim, Germany Filed May 27,1959, Ser. No.*816,177

Claims priority, application Germany May 29, 1958 26 Claims. (Cl. 74-.336.5)

The present invention relates to an electricshifting arrangement for change speed transmissions,especially 'for motor vehicles, in which the shifting members, for

example, the shifting forks are guided within the transmission in a rotatable guide disc member which is adapted to be selectively driven in either direction of rotation by an electric motor over a high speed reduction gear, for

example, over a worm gear drive.

In a prior-art shifting arrangement of-the type described hereinabove, the guide disc memberis drivendirectly' froman electric motor over a worm gear drive.

The driving motor is thereby directly controlled by the shifting impulses in the actuating or engaging circuits thereof. A disengageable clutch is thereby arranged between the guide disc member and the worm gear drive of the prior art. However, this prior-art arrangement is disadvantageous because of 'the presence of transmission shocks which occur as aresult of the inertia ormass of the driving motor. Furthermore, the exact positioning of the guide disc member in the individual shifting position after disengagement of the clutch is connected generally with difliculties.

The present invention aims at an elimination of the aforementioned disadvantages as well as at a simplification of the shifting arrangement. The problems connected therewith are solved in accordance with the present invention by providing the guide disc member along'the periphery thereof with a number of notches or detents corresponding to the respective shifting positions for purposes of accurately positioning the same in the individual shifting positions thereof while a latch member adapted to be actuated by a lifting magnet energized with the aid of the shifting impulses is adapted to engage in these detents or notches, and by arranging a slip-clutch between the electric motor energized by the shifting impulses, on the one hand, and the guide disc member, on the other, for purposes of avoiding any shocks in the drive arrangement for the guide disc member.

According to one embodiment of the present invention, the energizing coil of the lifting magnet may be operatively interconnected into the control circuits for both shifting directions, while the lifting magnet is adapted to be controlled directly by the shifting impulses and the energizing circuit of the motor is adapted to be controlled indirectly by a switch or relay which is actuated by a switching device, preferably by a multi-pole switch member operatively connected with the lifting magnet.

According to another embodiment of the present invention, the energizing coil for the lifting magnet is arranged in parallel to the energizing circuit of the motor, and both circuits are adapted to be controlled indirectly by means of relays from the control circuits for both shifting directions whereby the energizing circuit of the motor is adapted to be switched indirectly by means of a relay over a switch coordinated to or operatively connected with the lifting magnet. This switch, in addition to controlling the energizing circuit of the motor, may also control simultaneously therewith in both ergizingcircuit of the motor which furtherrelay is also ,controlledby the switchor contact at the. lifting magnet.

the :present invention.

embodiments according to. the present invenitonthe energizing circuit of an automatically actuated main clutch which isthereby controlled inthesame sense, i.e., that upon energization of the lifting magnet the main clutch is also disengaged.

The construction in accordance with the present invention provides a simple shifting arrangement readily supervised and serviced and reliable in operation by means of which an accurate positioning of the guide disc member in the individualtshifting positions thereof as well as a shock-free drive with suflicient shiftingvforces may be realized.

In the first embodiment of a shifting arrangement according to the .presentinvention as mentioned hereinabove, a relay is. arranged in theenergizing circuit for the motor ineachdirection of rotation whereby each relay is controlled by the corresponding control circuit for the respective shifting direction. Each relay may be provided with two energizing coils and with two contacts of which one each opens upon energization while the other one closes upon energization. The last-mentioned contact and one winding or coil thereby serve for. holding purposes of; the relay whereas the other winding or coil is arranged in the, control circuit for the. same shifting direction and the first-mentioned contact as lockout contact in the control circuit for the other shifting direction.

In the other embodiment according to .the present invention, a further relay is connected in parallel with the relay provided foreach direction of rotation-.injthe en- This further relay is operative over additional contacts as'holding relay for the energizing circuit of the motor. Furthermore, it is simultaneously, also effectivewith a construction as reversing switch as lock-out switch for the control circuit of the other shifting direction.

The shiftingarrangement in accordance with the present invention may be constructedv for manualactuation of the shifting impulses. In that case,,an actuating switch, for example, in the form of a pushbutton, is arranged in the control circuit for each shifting-direction and a selflocking or self-holding relay provided vwith actuating means actuated by the; guide disc itself is appropriately coordinated thereto in the holding circuit thereof.

Anautomatic actuation of the shifting impulse is also possible according to another featurein accordance with For that purpose, a centrifugal governor is arranged onthe transmission input shaft or is operatively connected therewith which .is operative to control with a respective shifting switch or contact each a control circuit, possibly arranged in parallel to themanually actuated control circuit, for achieving an automatic shifting operation in the upward and downward direction. A further shifting contact arranged at the centrifugal governor opens up all control circuits for the downward shifting operation as soon as the centrifugal governor attains a predetermined rotational speed which lies below the maximum rotational engine speed by a factor corresponding to the step or change in the transmission ratio between the prevailing and next lower speed. This prevents an excessive rotational speed ofthe engine by preventing the engagement of too low a speed of the change-speed transmission.

In order to prevent faulty shifting operations, different shifting positions, for example, the reverse speed and the neutral speed, are adapted to be engaged only by means of special manually-actuated switches or engaging means, whereby holding relays which are possibly providedwith special actuating or engaging means automatically actuated bytheguide disc-member in the respective shifting positions are operatively connected with these actuating or engaging switches in the holding circuits thereof.

Accordingly, it is an object of the present invention to provide a shifting arrangement for change speed transmissions which obviates the disadvantages previously encountered with similar prior art shifting arrangements.

Another object of the present invention resides in the provision of a shifting arrangement which is electrically controlled by a guide disc member selectively controlling the shifting members such as shifting forks of the change speed transmission to engage the respective individual speeds thereof and which obviates the need for an accurate positioning of the guide disc member in the various corresponding shifting positions thereof.

Still another object of the present invention lies in the provision of a shifting arrangement for change speed transmissions of the type mentioned hereinabove which is simple in construction and reliable in operation and which minimizes shifting shocks during shifting operations of the transmission.

Another object of the present invention is the provision of an electrically controlled shifting arrangement for change speed transmissions which assures freedom from faulty operation while providing at the same time adequate forces to effect reliably the shifting operations necessary for proper functioning of the control system.

Still another object of the present invention is the provision of a shifting arrangement for change speed a ing which shows, for purposes of illustration only, two

embodiments in accordance with the present invention, and wherein: p 1

Figure 1 is a schematic diagram of a shifting arrangement for a change speed transmission in accordance with the present invention, and

Figure 2 is a schematic diagram of another embodiment of a shifting arrangement for a change speed transmission in accordance with the present invention.

The present invention is particularly applicable to a chage speed transmission for a motor vehicle which also includes an automatically actuated main clutch. The various elements and circuits necessary for a complete understanding of the shifting arrangement in accordance with the present invention are shown more or less schematically in the two figures, while the actual change speed transmission with its shifting members and the main clutch of the vehicle are not shown herein since they may be of any conventional known construction which forms no part of the present invention.

Referring now to the drawing wherein like reference numerals are used throughout the two views to designate corresponding parts, the various speeds of the change speed transmission, indicated schematically, are shifted by means of a guide disc which is provided with special guide means 12, for example, in the form of slots or the like for the shifting forks 11 serving as shifting members of the transmission. The guide disc 10 is adapted to be rotated in both directions of rotation thereof, the clockwise direction of rotation thereof corresponding, for example, to an upward shifting operation and the counterclockwise direction of rotation to the downward shifting operation. The guide disc 10 is driven from an electric motor 13 which is operatively connected withtthe guide disc 10 over a speed reduction gear providing a large speed reduction, for example, over a worm gear drive and a slip clutch 14 adapted to provide a slippage under predetermined conditions. The slip clutch 14 is thereby used so as to permit the motor 13 to continue to rotate or run out for a relatively short of the motor 13, necessitated by reason of the inertia of the motor 13 making it impossible to stop the same instantaneously without transmitting thereby any shocks to the worm gear drive 15 and therewith to the guide disc member 10. The construction thereof in practice may also be made in s'ucha manner that the guide disc 10itself forms the worm gear wheel and accommodates or forms all of the other control cams or the like, as will be described more fully hereinafter.

Detents or notches 16 are provided along the periphery of the guide disc member 10 of which the number corresponds to the number of the shifting positions, i.e., for instance in the illustrated four-speed change speed transmission, a total of six notches 16. A latch member 17 is adapted to engage into the notches 16 under the influence of a spring or by gravitational force which is adapted to be lifted out of the notches 16 by a lifting magnet generally designated by reference numeral 18. A switching device 19 is connected with the armature of the lifting magnet 18 to which four switches S S S and S are coordinated. The switch S is thereby arranged in the energizing circuit 101 of the motor 13 leading from the positive terminal 24 of the power supply, such as the battery over switch S to a terminal 13:: of the motor 13 so that the latter is energized only indirectly upon energization of energizing coil 25 of the lifting magnet 18. One control circuit each to be described more fully hereinafter is provided for the 11pward and downward shifting operations respectively, and the energizing coil 25 of the lifting magnet 18 is operatively interconnected in both of these control circuits, as will appear more fully from the ensuing description.

A switch S is provided in the control circuit for the upward shifting operation and a switch S in the control circuit for the downward shifting operation for purposes of manual actuation thereof. Self-locking or holding relays R and R provided with separate engaging or actuating switches S and S respectively, actuated by the guide disc member 10 provided with appropriate cams are operatively connected with or coordinated to the switches S and S in the holding circuits thereof.

The selection of the direction of rotation of the motor 13 corresponding to the desired shifting direction also has to take place by the control circuits. For that purpose, two relays R and R are operatively connected with or coordinated to the windings (not shown) of motor 13. Each relay R and R is provided with two energizing windings 20, 20 and 21, 21', respectively, and two switch members 30, 22 and 31, 23, respectively, of which one switch member each opens upon energization of the corresponding relay whereas the other one closes upon energization thereof. The coil 20 of the relay R is arranged in the .control circuit for the upward shifting operation and the coil 21 of the relay R in the control circuit for the downward shifting operation. The other coils 20' and 21 are arranged as holding windings in series with the corresponding switches 30 and 31 operative to close upon energization so that the respective relay is automatically kept energized as soon as the motor 13 is supplied with current flowing through the corresponding winding. The switches 22 and 23 which open upon energization are operatively connected as lock-out switches in the control circuit for the other shifting direction respectively.

Manual operation In the position of the various parts illustrated in Figure 1, the transmission is in the neutral position thereof. If now, for example, for purposes of shifting in the upward direction into the first speed, the push-button switch S is actuated, then a control circuit is closed from the positive terminal 24 of the battery over energizing coil 25 of the lifting magnet 18,1ines 26 and 27, the closed disengaging switch S the holding relay R line 28, the switch S which is now closed, line 29, closed lock-out; contact 23 at the; relay R and the energizing'winding .20 of relay R to ground with which the negative terminal .of the battery not shown) is connected. :As,a result :and 1312, line 102-andcontact-30 nowclosedto provide a direction -of rotation of the. motor 1 -13..corresponding to the upward shifting operation of: the system. -At-the same time, thetliftingrmagnet ,ISttheIebyTJifts-tthe latch member 17 andv the motor 1 3,ro.tates.the guide disc. in a clockwise directioninto the position Ithereof corresponding to thenext. speed. 7

During actuation ofthepush-button ,"S stheholding relay R hasalso been energized as a ,resultof-the closure of seriescircuit described "hereinabove. Consequently, control current is also permitted to flow through: the circuit fromthe disengaging ,switchs over relay 3 directly to line 29 thereby effectively-forming a circuit in "parallel with push button 8 .so that'the switch S qnay again be released without-interrupting the continued flow of controlcurrent'inthe control circuit described hereinabove. This means in eifect'that the switch S has to be actuated only for a short period of time 'in order to initiate the upward shifting operation .and thereby shift the transmission to the next higher speed. De-energization of the control circuit described hereinabove takes place only when the disengaging switch S -is opened by one of the cams 32 provided on the guide disc member -10 whereby opening of switch S causes de-energization of relay R As a result thereof, the energizing coil 25 of the lifting magnet'18 is also de-energized. How- 'ever, the armature thereof may return into the initial position thereof when the next notch ordetent -16 of disc member 10 is positioned accurately below the latch member 17 whereupon the latter may return into the lowered position thereof illustrated in Figure 1. Return of the latch member 17 to the lower position thereof causes opening of switch S whereupon the motor 13 is -again.disc0nnected from the power supply and comes shortly thereafter to a stop. However, thetcam por- .tions 32 on disc member Iii-are so located that the disengaging switch S has already moved oifthe corresponding cam member 32 again when the .notch 16 isaccurately positioned underneath the latch member 17 .torpermit the latter to assume its lower position and is thereby again placed into readiness for thenextupward; shifting operation.

The switch S is actuated by -the switching member 19 during each actuation of the lifting magnetlS in'the same sense as the motor switch S whereby switch: S closes a circuit for actuating the automatically controlled main clutch of the vehicle over lines 33. In this manner, a disengagement of the'main clutch during each transmission shifting operation is achieved.

The upward shifting operation into second speed takes place in an analogous manner. If the switch S is pushed in for a longer period of time, then a shifting operation through several speeds, for example, from first into third speed maybe achieved. The upward shifting operation.

takes place only up to thehighest speed of the transmission, in the instant case up to fourth speed thereof. In this fourth-speed position, the relatively wider cam portion 34 provided at the guide disc member 10 keeps the disengaging switch S in the open position thereof so that the lifting magnet 18 can no longer be actuatedover the control circuit of the upward shifting operation as described hereinabove even if the push button S is. depressed.

The manual downward shifting operation takes place in a corresponding manner over switch or push button S however, only from the second to fourth speed thereof as only in these speeds the normally open disengaging switch s is closed by meet the cam portions 32.

'If the push-button S isactuated-in anyone of second;

. tive armatures thereof. and motor .13 thereby rotatesithe guide disc 18 in thecounterclockwise direction into ..a position for the next lower speed. The disengagement of the motor 13 as well as the readying of the control circuit for the -next shifting operation-takes place in an analogous manner as in .the upward shifting operation by cams 32.cooperating with the disengaging switch Automatic :shifling operation An automatic shifting operation controlled'by the centrifugal governor .38 is coordinated to the manual shifting arrangement in accordance with the present invention described hereinbefore. The centrifugal governor 38 is operatively connected with the transmission input shaft and is provided with three shifting contacts K K and K Theshifting contact K is arranged in a control circuit for the automatic upward shifting operation and is disposed in parallel with the switch S The centrifugal governor 38 thereby closes the contactK above :a predetermined rotational speed of, for example, 5500 rpm. In that case, the control current flows in a manner described hereinabove from positive terminal 24 through the energizing coil 25 of the lifting magnet 18, lines 26 and 27 into the line 28 and from there overzline 39, the normally closed switch S and contact K at the. centrifugal governor 38 which has now been automatically closed into line 40 which is operatively connected with the line 29. As a result thereof, the automatic control circuit for the upward shifting operation is closed and lifting magnet 18 is energized and thereby causes the upward shifting operation in the manner described hereinabove. During energization of the shifting magnet 18, the normally closed switch in the automatic control circuit is opened so that the disengagement after completion of the change in the engaged speed takes place in the manner already described hereinabove by relay R in connection with the disengaging switch 5 An automatic control circuit for the downward shifting operation is closed, for example, at a rotational speed below 1500 r.p.m. by the contact K also arranged at the centrifugal governor 38. This last-mentioned control circuit is arranged in a circuit including line 41 connected to line 36, normally closed switch S shifting switch K and line 42 connected to line 37, which is in parallel with the downward shifting switch S and is operative in a similar manner. If, for example, in fourth speed, the rotational speed of the transmission input shaft falls below 1500 rpm. by reason of an incline, then the contact K closes and control current is now permitted to fiow through the energizing coil 25 of the lifting magnet 18, line 35, disengaging switch S holding relay K; into the line 36. From line 36, the control circuit flows over line 41 and switch S shifting switch or contact K now closed and line 42 into the line 37. As a result thereof, the control circuit for the downward shifting operation is closed so that the downward shifting operation can take place in the manner described hereinabove. Upon energization of the lifting magnet 18, the switch S is opened by the shifting member 19 thereof and the automatic control circuit for the downward shifting operation is again interrupted so that after completing the change into the next speed, the disengagement of the downward shifting operation may take place again over switch S and-relay R; as described hereinabove.

A further shifting switch or contact K which-is intermission which is too low.

connected into line 37 is also operatively connected with the centrifugal governor 38.. The contact K is norlies below the maximum engine speed by a factor corresponding to the change in adjacent transmission ratios. In that case, i.e., as contact K opens, no downward shifting operation is any longer possible. This serves the purpose to prevent an excessive rotational speed of the engine I over and above its maximum engine speed by a downward shifting operation into a speed of the change speed trans- In order to achieve certain shifting positions, separate switches are provided which are adapted to be actuated exclusively manually. For example, for purposes of engaging neutral position of the change speed transmission, a special switch S is provided. The switch S which is provided with two contacts S and S is connected in a circuit which includes the line 26 and a line 43 connecting line 26 with both contacts S and S The switch S is operative in connection with both control circuits whereby a respective control is locked depending on the shifting position. Lines 44 and 45 lead from contacts 5;, and S respectively to the locking switches S7 and S which abut against the circumference of the guide disc 10 and to which a separate cam portion 46 is coordinated. 'In the neutral position of the shifting arrangement illustrated in Figure 1, both normally closed locking switches S and S are opened. If one of the forward speeds is engaged, then switch S7 moves off cam portion 46 and is thereby closed by reason of a corresponding position of the cam portion 46 which in the neutral position had kept the switch S open so that with an actuation of the neutral 2 switch S only the control and energizing circuit for the downward shifting operation over lines 26 and 43, contact S line 44, switch S and lines 47 and 48 is closed and the transmission is shifted downwardly into neutral.

'If, in contradistinction thereto, the transmission is en gaged in the reverse speed thereof, then the switch S moves off cam portion 46 and is thereby closed, whereas the switch S remains open. In that case, only the energizing control circuit for the upward shifting operation can be closed over lines 26 and 43, contact S line 45, switch S and line 49 connected with line 29 so that only an upward shifting operation into neutral position can take place within the transmission.

For purposes of engaging the reverse speed, a separate switch S is provided. The switch S isalso operatively connected with the line 26 over line 103. However, since in that case the downward shifting operation into reverse speed has to take place at all times, a cooperation with the switches S7 and S is not necessary. Consequently, switch S is operatively connected directly over lines 103, 50 and 48 with the line 37 for the downward shifting operation.

Holding relays may be coordinated to the switches S and S in a manner similar to switches S and S and relays R and R so that with either of these two lastmentioned switches S or 8,, only a relatively short depression of the respective switches is necessary in order to shift the transmission from a prevailing speed into the desired speed.

Such an arrangement is illustrated in the embodiment according to Figure 2. This embodiment is basically the same as that of Figure 1; however, all relays are arranged in this embodiment in parallel circuits so that any mutual influence or interference between relays is avoided. Fur- .thermore, the control of the energizing current for the motor 13 and the lifting magnet 18 is also improved thereby.

I The energizing circuit of the motor 13 is again controlled, corresponding to the desired direction of rotation, by two relays R and R provided with the switches or 'coniactsw30 and .31. which close upon energization of the respective relays. The energizing coils 20 and 21 of these relays R and R are connected with the positive terminal 24 of the battery, on the one hand, by parallel circuits including contact 53 0f control relay R and line 51 and contact 54 of control relay R and line 52, and line 55 and, on the other, are both connected wth the grounded negative battery terminal. over line 55' and the automatically actuated switch S controlled by "the lifting magnet 18. The lines 33 and 33 for the actu tion of the main clutch also branch ofi from line 55 and the positive battery terminal 24. The contact 31 of the relay R which'determines the downward shifting operation, controls simultaneously over an additionalcontact 58 a member 59 schematically illustrated and of conventional construction for influencing a reduction in the amount of fuel supplied, for example, by making suitable adjustments in the fuel supply ,as determined normally by the gas pedaLthrottle valve or adjusting rack of a fuel injection pump. a

Relays R and R are coordinated to relays R and R as holding relays the energizing coils 20' and 21' of which are arranged in parallel with the windings 20 and 21 of relays R and R The relays R and R are operative simultaneously with the contacts 22 and 23 thereof which open upon energization as lock-out switches for the other shifting direction. Additional contacts 56 and 57 are provided as holding contacts. Lines 29 and 37 for the control circuits of the upward and downward shifting operations are lead over the lock-out contacts 22 and 23 inthe manner already described hereinabove in connection with Figure 1.

The energizing coils 60 and 61 of the control relays R and R are arranged over lines 29' and 37' in parallel with respect to the control lines 29 and 37 respectively. One or the other of lines 29' and 37 are closed and therewith supplied with current upon energization of any one of the relays R to R The control relays R and R control over the contacts 62 and 63 thereof and over lines 64 and 65 the energizing coil 25 of the lifting magnet 18 as well as simultaneously therewith over contacts 53 and 54 the motor relays R and R as well as the holding relays R and R respectively.

Holding relays R to R are coordinated to all the switches S to S with the disengaging or looking switches S to S and S arranged in the holding circuits thereof. Two relays R and R with locking switches S and S are associated with neutral switch S because neutral switch S has to be able to initiate control impulses in one or the other shifting directions depending on the shifting position. All switches S to S on the one hand, are connected to ground. On the other hand, switches S and 8;, are connected over the engaging or locking switches S and S and the energizing windings of the corresponding relays R and R with the control line 29 for the upward shifting operation. The other switches S and S, as well as the relay R3 belonging to switch S are connected in a corresponding manner with the line 37 for the downward shifting operation which may again be interrupted by the contact K at the centrifugal governor 38. The switch S for the reverse speed is coordinated to the disconnecting switch S which is actuated by the cam portions 66 at the guide disk member 10.

The contacts K and K at the centrifugal governor 38 control the automatically controlled control circuits 6 7 and 68 which are arranged in parallel circuits with respect to the switches S and S The control circuits 67 and 68 are both operatively connected with the contact S at the lifting magnet 18 so that the switches S and S of the embodiment in Figure 1 may be dispensed with in this embodiment.

Furthermore, according to another feature of the present invention, it would be feasible to provide also an automatic downward shifting operation upon actuation of thebrake, for example, by depressing the foot pedal. For-that purpose, the downward shifting switch S; could be bypassed by a'further'contract S -which is arranged at therbrake pedal and which is closed when thebrake is-actuated. Suitable devices may thereby be incorporated into the linkage between the brake actuating device and contact 14 so that the latter is closed only when the brake is engaged by a predetermined amount and/ or in excess of a predetermined rate. A similar contact S may also be coordinated to the gas pedal .as aso-called kick-down shifting switch in order to achieveagreater acceleration by shifting to a lower'speedwhen the gas pedal is kicked down. Contact S isthereby also con- -nectedin parallel-with the downward shifting switch S "Operation The operation of .the embodimentofLFigure 2.corre--- sponds to that of'Figure 1. .The .transmisison is, for

example, in the'first speed'thereofand, theneutral switch "S is pushed down for a short period of time. Since in thisfirst-speed position, the 'swit'chS is open, Whereas for the relay R over line 113 and the circuit containing lines 113 and 114, line37','the energizing coil 61, line .37, contact 22 of relay R '.and line150' leading to the 'positive terminal.24 so that the control relay R is energized. As a result thereof, the lifting magnet 18 is supplied with current from terminal 24 overvcontacts 54 and 63, line 65, line' 64 and switchS1z whereupon "the latching. member 17 .is lifted out of recess 16 and 'theswitch S is reversed. .By the reversal of the switch T the energizing circuit for both relays R and R are closed over the circuit includingllines 55 and 55; windings 21 and 21', line 52' and contact 54 whereupon't'nese relays "R and R are closed and attracted their. respective 'armatures As a result thereofjthe motor 13 is energized for 'a' downward shifting operation and the lockout switch 23 for the upward shifting operation is opened. The motor 13, therefore, rotates the guide disc into the neutral position thereof.

As soon as the neutral position-is attained, the look-out switch S is opened by the cam portion 46 and the relay R is thereupon de-energized. As a result thereof, the relay R is also de-energized whereupon energization of the'lifting'magnet 18 is also discontinued. The'relays R and R however, remain energized over the holding circuit including contact 57 and switch 23 so that the motor continues to run for such'length of time until the latch member'17 is permitted to engage in the notch or detent 16 corresponding to neutral position. Only then, upon reversal of switch-S relays R and "R are also :de-energized and therewith the motor 13 is de-energized.

Otherwise, the shifting operations to the higher and lower speeds as well as to the reverse speed takes place in the same manner as in connection with Figure 1.

While we have shown and described two embodiments in accordance with the present invention, it'is understood that the same is not limited thereto but is susceptible of many changes and modifications within the spirit and scope of the present invention, and we, therefore, do not Wish to be limited to the embodiments'described and illustrated herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

We claim:

1. An electric shifting arrangement for change-speed transmissions, especially for motor vehicles, comprising shifting means for the change-speed transmission, rotatable guide means within said transmission for guiding said shifting means, electric drive means including an electric motor in series with speed reduction gear means for driving'said guide means from said electric .motor in either direction of rotation thereof, control means for producing electric shifting impulses, said guide means vmeans including. speed reduction gear means and slip clutch means forjdriving said-gu-ide means from said elecbeing provided alongthe periphery thereof with a iilirtv berzofnotches: corresponding tothe individualshifting positions, engageable means adapted toengage in .a

anotch when properlypositioned therebelow, and actuating means for selectivelyactuating said engageable means. in

the engagementand disengagement thereof in dependence on saidshifting impulses.

2. Anelectric shifting arrangement for change-speed .transmissions according to claim 1, wherein said control means includes means for selectively producing said shifting impulses.

3. An electric shifting arrangement for change-speed transmissions according to claim v1, wherein said control means includes means for. automatically producing said transmissions, especiallyfor motor vehicles, comprising shifting means, rotatable guide means within said transmission for .guiding. said .shiftingmeans, electric drive tric drivemeans in either. direction of rotation thereof,

=.control-means. for'producing electric shifting impulses,

said guide means being providedalong the periphery thereof-with anumberof-notches corresponding to the individual shifting positions, engageable means adapted to engage in a notch when properly positioned therebelow, and actuating-means for selectively actuating said engageablemeans in the engagement and disengagement thereof in dependence ,on said shifting impulses.

5. An-electric shifting arrangement for change-speed transmissions according to claim4, wherein said control means includes means for selectively producing said shifting impulses and means for automatically producing said impulses in dependence on the rotational speed of the .driving engine of the vehicle.

6. An electric shifting arrangement for change-speed transmissions,.especially for motor vehicles, comprising shifting means, rotatableguide diskmeans within said transmission for guiding said shifting means, electric drive means including an electric motor operatively connected with speed reduction gear means and slip clutch means for driving said guide disk means from said electric motor in either direction of rotation thereof, means for producing electric shifting impulses, said guide disk means being provided along the periphery thereof with a number of notches corresponding to the individual shifting positions, latch means adapted to engage in a notch when'properly positioned therebelow, and electromagnet means for selectively actuating said latch means in the engagement and disengagement thereof in dependence on said shifting impulses.

7. An electric shifting arrangement-for change-speed transmissions according to claim 6, wherein said control 'means includes a control circuit for an upward shifting operation and a control circuit for a downward shifting operation of. said transmission, energizing circuits for "said electric drive means to produce rotation in either direction, one of said energizing circuits corresponding to the control circuit. for the upward shifting operation and another energizing circuit corresponding to the control circuit for the downward shifting operation, said elec- 'tromagnetic means including an energizing winding and anenergizing'circuitfor said winding, and means connecting the energizingcircuit for said winding in the control circuits forboth shifting directions and for operatively connecting the energizing circuits with said control circuits to control said electromagnetic means directly by said shifting impulses and for controlling said energizing circuits indirectly by said shifting impulses.

8. An electric shifting arrangement for change-speed transmissions according to claim 7, wherein said connecting means includes switch means indirectly controlling the energizing circuits by said shifting impulses,-and further switch means operatively connected with said electromagnetic means for actuating said first-mentioned switch means.

9. An electric shifting arrangement for change-speed transmissions according to claim 6, wherein said control means includes control circuits for each direction of shifting operation and energizing circuits for said electric drive means to cause rotation of said electric drive means in a direction corresponding to the respective shifting dlrection, and means including relay means in each of said energizing circuits and operatively interconnecting said circuits with each other for controlling a respective relay means directly by the corresponding control circuit.

10. An electric shifting arrangement for change-speed transmissions according to claim 9, wherein each relay means is provided with two energizing windings and two contacts, one contact each opening upon energization and the other closing upon energization of a respective windmg.

11. An electric shifting arrangement for change-speed transmissions according to claim 10, further comprising holding circuit means including one of said energizing windings and one of said contacts while each of the other energizing windings for the same shifting direction and the other contact thereof are operatively connected in the control circuit of the other shifting direction and forming lock-out switch means.

'12. An electric shifting arrangement for change-speed transmissions according to claim 6, wherein said electric drive means includes energizing circuit means, wherein said control means includes control circuits operatively connected with relay means, and wherein said electromagnetic means includes an energizing winding arranged insparallel to the energizing circuit means for said electric drive means and is operative to be controlled by said relay means for both shifting directions, switch means operatively connected with said electromagnet means, and means including said relay means for indirectly controlling said energizing circuit means for said electric drive means over said switch means by said relay means.

trolled by said switch means operatively connected with said electnomagnet means, each of said further relays including contact means operatively connected with said control means to serve as holding relay for the respective energizing circuit means of said electric drive means and as lock-out switch for the other shifting direction.

14. An electric shifting arrangement for change-speed transmissions, especially for motor vehicles having a main clutch, comprising shifting means, rotatable guide means within said transmission for guiding said shifting means, electric drive means including speed reduction gear means and slip clutch means for driving said guide means from said electric motor in either direction of rotation thereof, means for producing electric shifting impulses, said guide means being provided along the periphery thereof with a number of notches corresponding to the individual shifting positions, engageable means adapted to engage in a disk means.

16. An electric shifting arrangement for change-speed transmissions adapted to be shifted in an upward and downward direction, especially for motor vehicles, comprising transmission shifting means, rotatable guide disk means within said transmission for guiding said shifting means, electric drive means including an electric motor drivingly connected with speed reduction gear means and slip clutch means for driving said guide disk means from said electric motor in either direction of rotation thereof, circuit means for producing electric shifting impulses including control circuit means for each shifting direction, said guide means being provided along the periphery thereof with a number of notches corresponding to the individual shifting positions, electromagnetically engageable means adapted to engage in a notch when properly positioned therebelow, motor energizing circuit means for energizing said motor to rotate in either direction of rotation thereof, and means operatively interconnecting said motor energizing circuit means, said control circuit means and said electromagnetically engageable means to shift said transmission in one or the other direction upon ene r gization of said motor energizing means and said electromagnetically engageable means; i

17. An electric shifting arrangement for change-speed transmissions according to claim 16, wherein said circuit means for producing electric shifting impulses includes centrifugal governor means operatively connected with the transmission input shaft including a plurality of contact means, and means operatively connecting a respective one of said contact means in a corresponding control circuit means to automatically shift the transmission in the upward or downward direction in dependence on the speed of said transmission input shaft.

18. An electric shifting arrangement for change-speed transmissions according to claim 17, wherein said circuit means for producing electric shifting impulses includes manually actuatable switch means arranged in parallel with said contact means.

19. An electric shifting arrangement for change-speed transmissions according to claim 18, wherein one of the contact means of said centrifugal governor means is operative to open up both the manually operated and automatically operated control circuit means for the downward shifting operation of said transmission as soon as said centrifugal governor means attains a rotational speed which is below the maximum permissive engine speed by a factor corresponding to the step in adjacent transmission ratios.

20. An electric shifting arrangement for change-speed transmissions according to claim 17, wherein each automatically controlled circuit means controlled by said contact means includes lock-out switch means opening upon energization of said electromagnetically engageable means.

21. An electric shifting arrangement for change-speed transmissions according to claim 17, wherein said electromagnetically engageable means includes a two-pole switch operatively connected therewith, and wherein all of the automatically controlled circuit means are operatively connected with said two-pole switch.

22. An electric shifting arrangement for change-speed transmissions according to claim 16, further comprising manually actuated switch means for the neutral position of the transmission including contact means for each shifting direction, and circuit means interconnecting said contact means with said control circuit means and including selectively engageable means automatically actuatedby said guide disk means in dependence on the shifting position and shifting direction thereof.

23. An electric shifting arrangement for change-speed transmissions according to claim 22, further comprising holding relay means operatively connected in parallel with said manually actuated switch means and operatively interconnected with said automatically engageable means automatically actuated by said cam disk means.

24. An electric shifting arrangement for change-speed transmissions according to claim 16, further comprising a manually actuatable reverse switch to engage the reverse speed of the transmission, means including holding relay means operatively connected with said last-mentioned switch to enable engagement of the reverse speed only by actuation of said last-mentioned switch, and cam means at said guide means for rendering said reverse switch selectively effective and ineffective.

25. An electric shifting arrangement for change-speed transmissions according to claim 6, wherein said guide disk means forms itself said notches and is provided with 14 cam means for the selective control of said means for producing electric shifting impulses.

26. -An electric shifting arrangement for change-speed transmissions according to claim 6, wherein said guide disk means is made of several disk portions each forming a part of the control surface of said guide disk means, said guide disk means including in addition to said notches cam means for operating said means for producing said 10 shifting impulses.

References Cited in the file of this patent UNITED STATES PATENTS 15 1,273,266 Patch July 23, 1918 1,446,806 Mathis Feb. 27, 1923 1,782,343 Dobbins Nov. 18, 1930 2,092,446 Fleischel Sept. 7, 1937 

